An existing subrack generally includes a chassis, a plurality of first main boards arranged in a front part of the chassis, and a plurality of second main boards arranged at a rear of the chassis. To facilitate heat dissipation of the subrack, a fan is usually installed at the rear of the subrack and an air inlet is arranged in the front part of the subrack. However, heat of the first main boards in the front part of the subrack is brought to the second main boards at the rear by such an air exhaustion manner, so that the second main boards at the rear are in a high-temperature environment for long, causing too fast ageing of the second main boards at the rear of the subrack and reducing device reliability.
This section provides background information related to the present disclosure which is not necessarily prior art.